A debate has been raging in the philosophy of mind for at least the past two decades. It concerns whether the mental can make a causal difference to the world. Suppose that I am reading the newspaper and it is getting dark. I switch on the light, and continue with my reading. One explanation of why my switching on of the light occurred is that a desiring with a particular content (that I continue reading), a noticing with a particular content (that it is getting dark), and a believing with a particular content (that by switching on the light I could continue reading) occurred in me, and these events caused my switching on of the light. This explanation works by citing the intentional contents of mental phenomena as causes of that action. It is because the intentional causes have the contents that they do, and because those contents play a causal role in bringing about my action, that my action is causally explained